A probabilistic technique for entrained air void analysis in hardened concrete

• We propose an alternative method to analyze entrained air voids in hardened concrete.
• A probabilistic 3D reconstruction is derived from 2D measurements.
• A new spacing factor is proposed and compared to the classic Powers spacing factor.
• The alternative spacing factor is an improvement over the classic spacing factor.

A novel method that utilizes the lineal-path function to ascertain a probability density function for the three-dimensional size distribution of entrained air voids directly from plane polished sections of hardened concrete is proposed. The results then treat the spacing factor in terms of a probabilistic maximum distance from a random point in the cement paste matrix to the periphery of an air void, where air voids are treated as a polydispersed sphere system. The model was applied to concretes with various air entrainment admixture types and dosages. The results suggest that the model may offer a better assessment of the system for use in assessing durability and studying admixtures, as well as providing a new tool for spatial characterization of heterogeneous and porous materials.